The invention relates to a method of producing a dielectric having a perowskite structure, comprised of stoichiometrical alkaline earth titanates, alkaline earth zirconates, alkaline earth stannates and mixed crystals thereof.
It is known that sintered ceramic mixes consisting of barium titanate or mixed crystals of barium titanate with calcium titanate and barium zirconate or strontium titanate or barium stannate, such as (Ba, Ca) (Ti, Zr)O.sub.3 ; Ba(Ti, Zr)O.sub.3 ; Ba(Ti, Sn)O.sub.3 ; (Ba, Sr)TiO.sub.3, are used as the dielectric in the production of ceramic capacitors. To obtain adequate ceramic densities, such materials must be sintered above 1300.degree. C., often even at temperatures around 1400.degree. C.
"Trans. Brit. Ceram. Soc." 74 (1975) No. 5, pages 165 to 169 discloses the use of admixtures of 0.5 mole % of copper to achieve dense sintering of barium titanate at sintering temperatures above 1200.degree. C. in a reproducible manner.
The high sintering temperatures used in the present state of the art present several problems. These problems include the pronounced interaction of the material to be sintered with the very expensive refractory materials used during sintering, consisting of, for example, zirconium oxide, the considerable wear of the sintering furnaces and the relatively high energy cost.